HIV infection is a disease caused by the human immunodeficiency virus (HIV). The condition gradually destroys the immune system, which makes it harder for the body to fight off infections.

This article provides a general overview. For more detailed information, see:

• AIDS
• Acute HIV infection
• Asymptomatic HIV infection
• Early symptomatic HIV infection

The human immunodeficiency virus (HIV) may be spread by the following:

• Intimate sexual contact
• The use of contaminated needles and syringes
• Contaminated blood transfusions and blood products

The virus may also spread through the placenta from the mother to her developing baby. It is rarely spread through breastfeeding.

People who become infected with HIV may have no symptoms for up to 10 years, but they can still pass the infection to others. After being exposed to the virus, blood tests results change from HIV negative to HIV positive usually within 3 months.

HIV has spread throughout the United States. Higher concentrations of the disease are found in inner cities.

HIV can cause any symptoms of illness, since infections can occur throughout the body. Special symptoms relating to HIV infection include:

• Diarrhea
• Fatigue
• Fever
• Frequent vaginal yeast infections
• Headache
• Mouth sores, including candidal infection
• Muscular stiffness or aching
• Rash of various types, including seborrheic dermatitis
• Sore throat
• Swollen lymph glands

Note: At the time of diagnosis with HIV infection, many people have not experienced any symptoms.

The HIV ELISA/Western blot test may be positive HIV antibodies. If it is negative and you have definite risk factors for HIV infection, you should be retested in 3 months.

Other blood tests can be done to determine how much HIV is in your bloodstream. Blood differential may show abnormalities.

A lower-than-normal CD4 cell count is a sign that the virus is suppressing the immune system.